1. Field of the Invention
The invention relates to the field of printing technology and is particularly suited for densitometers and printing machines.
2. Description of the Prior Art
It is specified in the DIN draft No. 16536, DK 655.3062.12:535.65, April, 1979, part 2, 4.1, Measuring Geometry, that the light incidence for measurement in densitometric measuring should be directed at an angle of 45.degree. relative to the surface normal line.
It has turned out, however, that in the measurement of densities of color layers of printing inks, the gloss of the ink which is still wet from printing falsifies the measurement when traditional densitometers are employed for measuring the specimens.
Further it is also necessary to continuously take density measurements of specimens for monitoring the color control in high-speed printing machines. This is necessary in order to be able to undertake a corresponding control or regulation of the amount of printing ink before the occurrence of inadmissible fluctuations in order to prevent these fluctuations.
If, given the measuring method taught in the prior art, one waits until the ink has been absorbed, then the operation to be regulated or controlled in, for example, the printing machine, occurs too late. That is, the regulation comes after an amount of spoilage has already arisen. Corresponding mis-measurements occur given the densitometer.